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1.
Nine dinucleotide microsatellites were developed in Astronium urundeuva (Anacardiaceae), a typical tree of the seasonally‐dry tropical forests of South America and characterized on three populations from Paraguay and Argentina. Seven microsatellites were found polymorphic in within population gene diversities ranging from 0.32 to 0.91, and an observed number of alleles varying between four and 20. Despite their relatively low number of alleles, these markers proved valuable tools in detecting genetic structure between three populations in Paraguay and North Argentina.  相似文献   

2.
Eleven dinucleotide microsatellites were developed in Geoffroea spinosa (Leguminosae), a widespread tree of the seasonally dry Neotropical forests, and characterized on six populations from Peru, Argentina and Paraguay. Four of them amplified on the Peruvian populations only, probably because of mutations in the microsatellite flanking regions in the other populations. Ten microsatellites were found polymorphic, with within population gene diversities ranging from 0.17 to 0.95, and a number of alleles varying from seven to 19. A significant overall genetic differentiation was also found (θ = 0.212; P < 0.01).  相似文献   

3.
Chronic anthropogenic disturbances and climate change have been recognized as drivers of biological reorganization across human-modified tropical landscapes, also negatively affecting the reproductive output of some plant species. Here, we investigated to what extent these drivers affect the reproductive output of Cenostigma microphyllum, a disturbance-adapted tree species endemic to the Caatinga dry forest. The production of flowers/inflorescence, fruits and seeds was estimated for 105 plants (≥3 cm diameter at soil height) across 11 forest stands (20 × 50 m each), covering gradients of chronic disturbances (e.g. goat and livestock herbivory; wood extraction; and removal of non-timber forest products) and aridity at the Catimbau National Park. We documented that when the drivers were analysed in isolation, the fruit-set was positively associated with increased wood extraction, and the fruit-set and total number of seeds/plots were reduced under increasing aridity. We also verified a complex interaction between wood extraction and aridity emerged. In forest stands, the combination of high levels of aridity and wood extraction leads to a decrease in the fruit-set and total number of seeds/plots. Conversely, the fruit-set and total number of seeds/plots increased in stands exposed to lower aridity but high levels of wood extraction. Our results suggest that chronic disturbances and aridity affect plant fitness in a complex way including both negative and positive effects on attributes related to plant reproductive performance, which could result in both proliferation and population decline in the same landscape. Although C. microphyllum benefits from anthropogenic disturbances and is considered a disturbance-adapted species, it apparently does not benefit from increases in aridity, which is an expected future scenario for the Caatinga dry forest.  相似文献   

4.
A phylogenetic analysis of combined morphological, chemical and ITS/5.8S sequence data reveals that species of Ateleia are often more genetically than morphologically divergent, and that species thought to be most closely related morphologically are distant relatives within the genus. Ateleia shows niche conservatism, with most species confined to seasonally dry tropical forest in Central America and the Caribbean, and fewer species in the same biome in South America. Four independent transitions to wet forests may have occurred in the genus. The estimated ages of Ateleia lineages spanning Central and South America are either older or younger than the estimated age of closure of the Isthmus of Panama. The older dates clearly suggest that over‐water dispersal is responsible for the distribution of Ateleia that includes the Caribbean Islands. © 2010 The Linnean Society of London, Botanical Journal of the Linnean Society, 2010, 162 , 39–53.  相似文献   

5.
Ipomoea microdactyla Griseb. (Convolvulaceae) is restricted to the Bahamian archipelago, Cuba, and southeastern Florida. The species is listed as a state endangered species in Florida, where it is mostly restricted to the hyperfragmented pine rockland of Miami‐Dade County. Using seven DNA microsatellite loci, we assessed levels of genetic diversity for 12 populations of this species from Andros Island in the Bahamas (six sites), Cuba (one site), and Florida (five sites). We found significantly greater mean numbers of alleles, and higher mean values for both observed and expected heterozygosity in populations from the continuous forest on Andros than those from the habitat fragments in Florida. It is unknown if these patterns of genetic diversity in the Florida populations are the result of habitat fragmentation or founder effects. The population from Cuba exhibited relatively high levels of genetic variation, suggesting that this island is a major center of diversity and dispersal for this species. It appears that hybrid introgression for I. carolina alleles within I. microdactyla individuals occurred at a single site on Andros Island. Overall, the mean inbreeding coefficient value was 0.089, suggesting low levels of inbreeding. The highest inbreeding coefficient values were mostly recorded in Florida. Two groups were revealed, one containing the populations from Florida, and the second one encompassing those from the Bahamas and Cuba. Our results highlight the negative genetic consequences of habitat fragmentation and support initiatives recently established to establish corridors to connect the remnants of the pine forest of the Miami‐Dade County.  相似文献   

6.
Two new species of Neoibidionini from Colombia are described: Psiloibidion boteroi n. sp. and Tropidion neisi n. sp. The previous key to species of Tropidion is modified to include the new species. The females of Compsibidion paradoxum Martins, 1971 and Glomibidion trinidadense (Gilmour, 1963) are described and illustrated for the first time. Moreover, the geographical distribution is expanded for nine species of Neoibidionini.  相似文献   

7.
  • The impacts of the historical geologic and climatic events on the diversity and genetic structure of Neotropical taxa have recently become a subject of study. However, annual plants associated with tropical dry forests remain under‐studied. The exploration of additional taxa in contrasting environments will improve the current understanding of responses of the Neotropical biota to these events. Here, we explore the species distribution and geographic structure of the annual herb Tithonia rotundifolia.
  • We sampled 175 individuals from 19 populations of T. rotundifolia. Species distribution modelling and six microsatellite chloroplast loci were used to infer its population history. We identified areas of historical climate suitability and then tested if there is genetic structuring among these areas.
  • Haplotypes showed strong phylogeographic structure. Historical climatic suitability areas were found along the Pacific coast; however, a gap was found at the Isthmus of Tehuantepec (IT). Although Bayesian analysis showed population structuring, amova revealed that the IT is not its main driver. Instead, a subdivision into a higher number of regions had higher FCT values. Also, populations to the east of the IT showed evidence of recent population expansion and migration in a south–north direction.
  • Pleistocene climate fluctuations partially explain the geographic structure of T. rotundifolia. However, life‐history characteristics such as limited seed dispersal and the patchy distribution of suitable habitats explain the high haplotype diversity and population sub‐structuring and diversity. Lastly, the absence of geographic structure of some haplotypes may indicate long‐distance dispersal, or hybridisation with the closely related T. tubaeformis.
  相似文献   

8.
George K. Rogers 《Brittonia》2000,52(3):218-233
The genusAgave (Agavaceae) is revised taxonomically for the Lesser Antilles. All 12 previously recognized species are placed into synonymy underAgave karatto Miller. A neotype is selected for the nameAgave karatto, and lectotypes are designated forA. barbadensis Trel.,A. medioxima Trel.,A. obducta Trel.,A. vangrolae Trel., andA. ventum-versa Trel. Specimens are cited for most of the Lesser Antillean islands. That the Caribbean agaves are similar to the MexicanAgave nayaritensis Gentry is supported. The hypothesis that the pattern of partial sterility, clonality, and minimal morphological differentiation of the Lesser Antillean agaves is related to prehistoric human activity is developed based on similar patterns among mainland agaves and historical information. Uses for the archaeological “Barbados shell tool” may have included decorticating agave leaves for fiber extraction.  相似文献   

9.
Fossils of the genus Leptoptilos from the Pleistocene of Liang Bua, Flores, Indonesia, belong to a new species of giant marabou stork, Leptoptilos robustus sp. nov. This giant bird, estimated at 1.80 m in length, was similar in dimensions to extant Leptoptilos dubius, except for the tibiotarsus. The thick cortical bone wall of the tibiotarsus and the estimated weight of 16 kg imply a reduced flight capability. Osteological and biometric characters suggest that L. robustus is most closely related to L. dubius. An evolutionary lineage is proposed in which a volant L. dubius‐like ancestor in the Middle Pleistocene evolved into the Late Pleistocene L. robustus on Flores, with a concomitant reduction of the ability to fly and an increase in body size. The large body size and terrestrial lifestyle of L. robustus are responses to an unbalanced, insular environment with abundant prey items and a lack of mammalian carnivores, and emphasize the extraordinary nature of the Homo floresiensis fauna. © 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160 , 707–724.  相似文献   

10.
Caesalpinia oyamae, a new species from the Río Balsas Depression, Mexico, is described and illustrated based on morphological evidence. It is similar toCaesalpinia hintonii, and grows in seasonally dry forests, between 500–1490 m.  相似文献   

11.
TheAntennaria rosea polyploid agamic complex is one of the most morphologically diverse and widespread complexes of N. AmericanAntennaria. The group is taxonomically confusing because of numerous agamospermous microspecies, having been recognized as distinct species. Morphometric analyses have demonstrated that the primary source of morphological variability in the complex derives from six sexually reproducing progenitors,A. aromatica, A. corymbosa, A. media, A. microphylla, A. racemona, andA. umbrinella. Additionally, two other sexually reproducing species,A. marginata andA. rosulata, may have contributed to the genetic complexity of theA. rosea complex. Cluster analysis indicates that four discrete morphological groups exist within theA. rosea complex. Each group could be the result of predominance of genes from different groups of sexual progenitors. AsA. rosea is of multiple hybrid origin, from among several sexual progenitors, it is advisable to recognizeA. rosea as a distinct species from its sexual progenitors.Investigations into the evolutionary history of the polyploid complexes inAntennaria (Asteraceae: Inuleae). 3. TheA. rosea complex.  相似文献   

12.
13.
The female of Eremobittacusspinulatus Byers, 1997 is described for the first time. A key to the two species known of this genus endemic to Mexico is provided, and species distribution is illustrated. A case is made for adults of Eremobittacus to be sexually dimorphic, which appears to be an exceptional occurrence in Bittacidae. It is claimed that Eremobittacusspinulatus habitus has a wasp-like appearance, which may potentially depict a case of mimicry.  相似文献   

14.
Sinomicrurus japonicus has a conspicuous colour pattern of longitudinal black stripes and transverse sets of black and white bands with an orange‐reddish background colour. The pattern varies markedly among island populations, and thus, three subspecies have been recognized. We conducted molecular phylogenetic analyses on the island populations to clarify the evolutionary trajectory of such colour patterns and reevaluate the current classification accordingly. The results indicated relatively deep allopatric divergences within S. j. boettgeri, paraphyly of S. j. boettgeri against other two subspecies, and two independent derivations of S. j. takarai from boettgeri‐like ancestors. Detailed morphological analyses revealed that variations in the boettgeri and takarai forms were more or less continuous and that differences between the two takarai populations were very small. From these results, we propose synonymizing S. j. takarai with S. j. boettgeri. Morphological differences between the genetically most distant populations of S. j. boettgeri were also small, whereas the japonicus form was distinct from the remainder. Considering the possible evolution of S. j. japonicus through peripheral isolation, we propose retention of these two subspecies. This study provides a basis for future work on the adaptive significance of geographic variation in the colour pattern of S. japonicus.  相似文献   

15.
BACKGROUND AND AIMS: Genetic structure and variability were examined in the only three extant populations of the narrow-endemic tree Antirhea aromatica (Rubiaceae, Guettardeae), an endangered species of the tropical forest of eastern Mexico. Patterns of genetic diversity within and among populations for adult plants and seedlings were obtained. METHODS: Allozyme electrophoresis of 15 loci was conducted and the data analysed with statistical approximation for obtaining genetic diversity, structure and gene flow. KEY RESULTS: The mean expected heterozygosity (He) in the adult and seedling populations was 0.18 +/- 0.08 and 0.20 +/- 0.09, respectively. The genetic variation explained by differences among populations was 51 and 35 %, for adult and seedling populations, respectively. On average, gene flow between paired adult populations was low (Nm = 0.26 +/- 0.09), compared with other trees from the tropical forest. CONCLUSIONS: The results indicated that the populations evaluated have high genetic variability, compared with other endemic and geographically narrowly distributed plant species, in areas with high levels of environmental heterogeneity (e.g. tropical forests). The conservation implications of the results are discussed, and in this regard it is proposed that A. aromatica should be considered as an indicator species with economic potential. It is suggested that sustainable management practices should be implemented and that the areas where the species is distributed should be declared a natural reserve to ensure the species conservation.  相似文献   

16.
17.
Nikoides schmitti is widely distributed along the Atlantic coast of the Americas, from North Carolina to Bahia, Brazil and Cuba and Guadeloupe; however, the knowledge about their reproductive biology is poorly known. In this study, data such as sex ratio, fecundity, size and volume of the embryos, and brood loss of material collected in July 1997 from Mahahual, Quintana Roo, Mexico is provided. The sample of 728 specimens had a sex ratio of 0.40 males per female. Fecundity (N = 31) of ovigerous females (Stage I) varied from 219 to 817, with an average of 432 ± 177 embryos. The newly extruded embryos of N. schmitti were small (0.41 ± 0.030 mm) and similar in size to those reported for other species of the genus. The mean volume of the embryos changed significantly during development, increasing 60.9% from stages I to III. Embryo loss during incubation was estimated in 32.9%. This study provides baseline information about the reproduction of N. schmitti and contributes to a better knowledge of this species little studied.  相似文献   

18.
BACKGROUND AND AIMS: The monoecious, bird-pollinated epiphytic Tillandsia achyrostachys E. Morr. ex Baker var. achyrostachys is an endemic bromeliad of the tropical dry forests of Mexico with clonal growth. In the Sierra de Huautla Natural Reserve this species shows a host preference for Bursera copallifera (Sessé & Moc ex. DC) Bullock. As a result of deforestation in the study area, B. copallifera has become a rare tree species in the remaining forest patches. This human-induced disturbance has directly affected the population densities of T. achyrostachys. In this study the genetic consequences of habitat fragmentation were assessed by comparing the genetic diversity, gene flow and genetic differentiation in six populations of T. achyrostachys in the Sierra de Huautla Natural Reserve, Mexico. METHODS: Allozyme electrophoresis of sixteen loci (eleven polymorphic and five monomorphic) were used. The data were analysed with standard statistical approximations for obtaining diversity, genetic structure and gene flow. KEY RESULTS: Genetic diversity and allelic richness were: HE = 0.21 +/- 0.02, A = 1.86 +/- 0.08, respectively. F-statistics revealed a deficiency of heterozygous plants in all populations (Fit = 0.65 +/- 0.02 and Fis = 0.43 +/- 0.06). Significant genetic differentiation between populations was detected (Fst = 0.39 +/- 0.07). Average gene flow between pairs of populations was relatively low and had high variation (Nm = 0.46 +/- 0.21), which denotes a pattern of isolation by distance. The genetic structure of populations of T. achyrostachys suggests that habitat fragmentation has reduced allelic richness and genetic diversity, and increased significant genetic differentiation (by approx. 40 %) between populations. CONCLUSIONS: The F-statistic values (>0) and the level of gene flow found suggest that habitat fragmentation has broken up the former population structure. In this context, it is proposed that the host trees of T. achyrostachys should be considered as a conservation priority, since they represent the limiting factor to bromeliad population growth and connectivity.  相似文献   

19.
The temporal dimension of the most recent Corallinaceae (order Corallinales) phylogeny was presented here, based on first occurrence time estimates from the fossil record. Calibration of the molecular clock of the genetic marker SSU entailed a separation of Corallinales from Hapalidiales in the Albian (Early Cretaceous ~105 mya). Neither the calibration nor the fossil record resolved the succession of appearance of the first three emerging subfamilies: Mastophoroideae, Corallinoideae, and Neogoniolithoideae. The development of the tetra/bisporangial conceptacle roofs by filaments surrounding and interspersed among the sporangial initials was an evolutionary novelty emerging at the Cretaceous–Paleogene boundary (~66 mya). This novelty was shared by the subfamilies Hydrolithoideae, Metagoniolithoideae, and Lithophylloideae, which diverged in the early Paleogene. Subclades within the Metagoniolithoideae and Lithophylloideae diversified in the late Oligocene–middle Miocene (~28–12 mya). The most common reef corallinaceans (Hydrolithon, Porolithon, Harveylithon, “Pneophyllum” conicum, and subclades within Lithophylloideae) appeared in this interval in the Indo‐Australian Archipelago.  相似文献   

20.
We determined the effect of forest fragmentation on the nectarivorous Colima long‐nosed bat (Musonycteris harrisoni) by observing foraging behavior of this species in disturbed and undisturbed forests on the flowers of Ceiba grandiflora (Bombacaceae). The study was conducted in the area of the Chamela‐Cuixmala Biosphere Reserve in Jalisco, Mexico. Musonycteris harrisoni was observed visiting flowers during six nights (88 visits), exclusively in undisturbed forest. This species feeds on the nectar and serves as a pollinator of C. grandiflora.  相似文献   

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